opelly/Stockfish
1
0
Fork 0
mirror of https://github.com/opelly27/Stockfish.git synced 2026-05-20 12:07:43 +00:00
Code Issues Packages Projects Releases Wiki Activity

Flag critical search tree in hash table

Browse Source 
Introducing new concept, saving principal lines into the transposition table
to generate a "critical search tree" which we can reuse later for intelligent
pruning/extension decisions.

For instance in this patch we just reduce reduction for these lines. But a lot
of other ideas are possible.

To go further : tune some parameters, how to add or remove lines from the
critical search tree, how to use these lines in search choices, etc.

STC :
LLR: 2.94 (-2.94,2.94) [0.50,4.50]
Total: 59761 W: 13321 L: 12863 D: 33577 +2.23 ELO
http://tests.stockfishchess.org/tests/view/5c34da5d0ebc596a450c53d3

LTC :
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 26826 W: 4439 L: 4191 D: 18196 +2.9 ELO
http://tests.stockfishchess.org/tests/view/5c35ceb00ebc596a450c65b2

Special thanks to Miguel Lahoz for his help in transposition table in/out.

Bench: 3399866
This commit is contained in:
MJZ1977
2019-01-09 15:05:28 +01:00
committed by Stéphane Nicolet
parent f69106f7bb
commit 70880b8e24
4 changed files with 31 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/search.cpp
+19 -7
View File
@@ -577,7 +577,7 @@ namespace {
Move ttMove, move, excludedMove, bestMove;
Depth extension, newDepth;
Value bestValue, value, ttValue, eval, maxValue, pureStaticEval;
bool ttHit, inCheck, givesCheck, improving;
bool ttHit, pvHit, inCheck, givesCheck, improving;
bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact;
Piece movedPiece;
int moveCount, captureCount, quietCount;
@@ -643,6 +643,7 @@ namespace {
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0]
: ttHit ? tte->move() : MOVE_NONE;
pvHit = ttHit ? tte->pv_hit() : false;
// At non-PV nodes we check for an early TT cutoff
if ( !PvNode
@@ -676,6 +677,11 @@ namespace {
return ttValue;
}
if ( depth > 6 * ONE_PLY
&& !excludedMove
&& PvNode)
pvHit = true;
// Step 5. Tablebases probe
if (!rootNode && TB::Cardinality)
{
@@ -709,7 +715,7 @@ namespace {
if ( b == BOUND_EXACT
|| (b == BOUND_LOWER ? value >= beta : value <= alpha))
{
tte->save(posKey, value_to_tt(value, ss->ply), b,
tte->save(posKey, value_to_tt(value, ss->ply), pvHit, b,
std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY),
MOVE_NONE, VALUE_NONE);
@@ -760,7 +766,7 @@ namespace {
else
ss->staticEval = eval = pureStaticEval = -(ss-1)->staticEval + 2 * Eval::Tempo;
tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, pureStaticEval);
tte->save(posKey, VALUE_NONE, pvHit, BOUND_NONE, DEPTH_NONE, MOVE_NONE, pureStaticEval);
}
// Step 7. Razoring (~2 Elo)
@@ -875,6 +881,7 @@ namespace {
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
ttMove = ttHit ? tte->move() : MOVE_NONE;
pvHit = ttHit ? tte->pv_hit() : false;
}
moves_loop: // When in check, search starts from here
@@ -1035,6 +1042,10 @@ moves_loop: // When in check, search starts from here
{
Depth r = reduction<PvNode>(improving, depth, moveCount);
// Decrease reduction if position is or has been on the PV
if (pvHit && !PvNode)
r -= ONE_PLY;
// Decrease reduction if opponent's move count is high (~10 Elo)
if ((ss-1)->moveCount > 15)
r -= ONE_PLY;
@@ -1217,7 +1228,7 @@ moves_loop: // When in check, search starts from here
bestValue = std::min(bestValue, maxValue);
if (!excludedMove)
tte->save(posKey, value_to_tt(bestValue, ss->ply),
tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit,
bestValue >= beta ? BOUND_LOWER :
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
depth, bestMove, pureStaticEval);
@@ -1247,7 +1258,7 @@ moves_loop: // When in check, search starts from here
Move ttMove, move, bestMove;
Depth ttDepth;
Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
bool ttHit, inCheck, givesCheck, evasionPrunable;
bool ttHit, pvHit, inCheck, givesCheck, evasionPrunable;
int moveCount;
if (PvNode)
@@ -1281,6 +1292,7 @@ moves_loop: // When in check, search starts from here
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
ttMove = ttHit ? tte->move() : MOVE_NONE;
pvHit = ttHit ? tte->pv_hit() : false;
if ( !PvNode
&& ttHit
@@ -1318,7 +1330,7 @@ moves_loop: // When in check, search starts from here
if (bestValue >= beta)
{
if (!ttHit)
tte->save(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER,
tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit, BOUND_LOWER,
DEPTH_NONE, MOVE_NONE, ss->staticEval);
return bestValue;
@@ -1429,7 +1441,7 @@ moves_loop: // When in check, search starts from here
if (inCheck && bestValue == -VALUE_INFINITE)
return mated_in(ss->ply); // Plies to mate from the root
tte->save(posKey, value_to_tt(bestValue, ss->ply),
tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit,
bestValue >= beta ? BOUND_LOWER :
PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER,
ttDepth, bestMove, ss->staticEval);